E. L4 – Explanation
Lower back pain: prolapsed disc
A prolapsed lumbar disc usually produces clear dermatomal leg pain associated with neurological
deficits.
Features
- leg pain usually worse than back
- pain often worse when sitting
The table below demonstrates the expected features according to the level of compression:
| L3 nerve root compression | Sensory loss over anterior thigh Weak quadriceps Reduced knee reflex Positive femoral stretch test |
| L4 nerve root compression | Sensory loss anterior aspect of knee Weak quadriceps Reduced knee reflex Positive femoral stretch test |
| L5 nerve root compression | Sensory loss dorsum of foot Weakness in foot and big toe dorsiflexion Reflexes intact Positive sciatic nerve stretch test |
| S1 nerve root compression | Sensory loss posterolateral aspect of leg and lateral aspect of foot Weakness in plantar flexion of foot Reduced ankle reflex Positive sciatic nerve stretch test |
Management
- similar to that of other musculoskeletal lower back pain: analgesia, physiotherapy, exercises
- if symptoms persist then referral for consideration of MRI is appropriate
